Ignition system

ABSTRACT

An ignition system is disclosed which includes a primary circuit having a battery, the primary winding of an ignition coil and an electronic valve controlling energization of the primary winding by the battery; a secondary circuit having the secondary winding of the ignition coil, a plurality of contacts adapted to be connected to combustion ignition devices and a distributor mounted to sequentially complete electrical connection between the secondary winding and each contact and triggering means including at least one wire mounted on a rotor, the wire having a shell and core of different coercivity, a magnet for reversing the magnetic polarity of the core, and a sensing head for sensing a change in magnetic flux around the wire which is produced in response to the occurrence of predetermined criteria, the sensing head providing a signal for controlling the electronic valve.

United States Patent Wiegand Sept. 11, 1973 1 IGNITION SYSTEM [75] Inventor: John Richard Wiegand, Valley Primary Goodndge Stream L 1. Assistant Exammer--Cort Flint Attorney-Laurence R. Hefter et al. [731 Assignees: Milton Velinsky, Plainfield, N.J.;

John R. Wiegand, Valley Stream, N.Y. part interest to each.

[57] ABSTRACT An ignition system is disclosed which includes a primary circuit having a battery, the primary winding of an ignition coil and an electronic valve controlling energization of the primary winding by the battery; a secondary circuit having the secondary winding of the ignition coil, a plurality of contacts adapted to be connected to combustion ignition devices and a distributor mounted to sequentially complete electrical connection between the secondary winding and each contact and triggering means including at least one wire mounted on a rotor, the wire having a shell and core of different coercivity, a magnet for reversing the magnetic polarity of the core, and a sensing head for sens ing a change in magnetic flux around the wire which is produced in response to the occurrence of predetermined criteria, the sensing head providing a signal for controlling the electronic valve.

20 Claims, 6 Drawing Figures [22] Filed: Sept. 28, 1971 [21] Appl. No.: 184,506

[52] US. Cl. 123/148 E, 123/146.5 A

[51] Int. Cl. F02p 3/02 [58] Field of Search 123/148 E, 146.5 A; 340/174 [56] References Cited UNITED STATES PATENTS 3,417,382 l2/l968 Snyder et al 340/174 ZB 3,451,793 6/1969 Matsushita 340/174 PW 3,452,730 7/1969 Stephens..... 123/148 E 3,534,719 10/1970 Minks 123/148 E 3,587,550 6/1971 Zechlin.... 123/146.5 A

3,587,551 6/1971 Harrow 123/148 E 3,683,339 8/1972 Kai 340/174 28 IGNITION SYSTEM BACKGROUND This invention relates to ignition systems, and, more particularly, to an ignition distributor which conveys a high electric voltage to spark plugs according a particular firing order and with precise timing and reliability.

Ignition distributors for internal combustion engines conventionally include a distributor shaft connected to a drive pinion in the engine block so that the distributor shaft rotates at the same speed as does the cam shaft of the engine. The distributor shaft carries a contactbreaker cam having a plurality of lobes, the number of which correspond to the number of spark plugs to be energized. A movable breaker point or contact lever is pivotally mounted adjacent to the cam and a stationary breaker point is fixedly mounted adjacent to the cam, the contact lever being spring loaded so that it normally touches the stationary point. A distributor rotor is mounted on the upper end of the distributor shaft and has an electrode which extends outwardly toward a plurality of stationary contacts which, in turn, are electrically connected to the spark plugs.

The primary portion of the ignition circuit includes a low voltage battery (6 or 12 volts) in series with a primary winding of an ignition coil, and the movable and fixed breaker points. When the points are in contact current flows through the primary winding generating a magnetic field and when the contact-breaker cam separates the points effecting interruption of the primary circuit, the magnetic field produced by the primary winding collapses inducing a high voltage (in the tens of thousands) in a secondary winding mounted adjacent to the primary winding. The induced voltage is applied to a particular contact and, through the contact, to a spark plug resulting in the production of a spark.

Many attempts have been made to eliminate the make and break relationship between the movable and fixed breaker points because the breaker points contaminate and wear out. The gap between the points is critical and if the gap is too small, interruption of the primary circuit at high speeds often does not occur, resulting in failure to tire the spark plugs. If the gap is too large the engine is difficult to start. Furthermore, because the make and break relationship between the points depends upon the spring return of the contact lever toward the fixed point, missing often occurs at high speeds even with properly gapped points. Engine misfiring caused by faulty breaker points is one major cause of air pollution due to emission ofnoxious gases. It also results in inefficient combustion requiring more fuel than would otherwise be consumed, contaminating other parts such as spark plugs and amplifying the air pollution problem.

In spite of the many attempts to overcome these disadvantages, no satisfactory system presently exists. Several magnetic inductive systems have been developed to overcome the need for the breaker points. However, these systems are unsatisfactory because either a) they have been unable to produce sufficient energy at low speeds to properly fire the spark plugs or they produce too much energy at very high speeds which tend to damage or prematurely wear out the spark plugs, or b) timing of the spark plug firing is not sufficiently accurate.

Accordingly, it is an objective of this invention to provide an ignition system which operates effectively and efficiently for long periods of time without the need for frequent maintenance and part replacement and which operates equally well at high and low speeds.

It is another objective of this invention to provide an ignition system which obviates the need for the conventional make and break" contact system thereby reducing maintenance costs and improving the operation of the engine.

A further objective of this invention is to provide an ignition system which may be manufactured easily and inexpensively and which may be utilized in the ignition system of existing engines.

BRIEF DESCRIPTION Briefly described, this invention in one form comprises an ignition system having a primary circuit, a trigger for actuating the primary circuit and a secondary circuit responsive to the primary circuit. The secondary circuit is conventional and includes a secondary winding of an ignition coil and conventional circuitry associated therewith having a distributor rotor, contacts and leads to individual spark: plugs. The primary circuit includes a conventional primary winding of the ignition coil. However, the conventional contactbreaker cam and movable and fixed breaker points are replaced by an electronic valve which is actuated withprecision timing by the triggering means.

A preferred form of the triggering means of this invention includes a rotary member drivingly connected to the cam shaft of an engine and having a plurality of wires equiangularly spaced thereabout. Each wire is formed to have a shell and central core, the shell having the capacity to be permanently magnetized in an axial direction and having a high coercivity. The core has a relatively low coercivity and the capacity to be magnetized in a first generally axial direction by the shell. The magnetization of the core is reversible by application of a second magnetic field having a direction reverse to that of the shell and a magnitude greater than that of the shell and, when the second magnetic field is removed, the magnetic field of the shell remagnetizes the core in the first axial direction. A sensor is mounted adjacent to the rotor and, in one form, includes a pennanent magnet having a magnetic field greater in strength than that of the wire shell and reversed in direction to the field of the shell. The sensor also includes a conductive wire coil. As each wire becomes juxtaposed to the sensor, the sensor magnet effects reversal of the direction of the magnetic field of the core and as the wire passes the field of the sensor magnet, the shell magnetically captures the core significantly modifying the magnetic field to which the sensor coil is exposed. This field change induces a current in the sensor coil. The induced current is amplified and directed to the control element of the electronic valve which is connected in series with a battery and the primary winding of the ignition coil. As the rotary member turns, each time a wire becomesjuxtaposed to the sensor a pulse is generated which closes the electronic valve resulting in the passage of a current through the primary winding. The current through the primary winding generates a magnetic field which induces a greatly increased voltage in the step-up secondary winding of the ignition coil. The higher voltage of the secondary winding is directed to the particular contact which corresponds to the wire on the rotor which is juxtaposed to the sensor and to a specific spark plug effecting generation of a spark to fire the combustion mixture within the cylinder in which the spark plug is mounted.

Since the pulse generated by reversal of the wire cores magnetic field in juxtaposition to the sensor is amplified to a level sufficient to trigger the electronic valve and since the current passing through the primary coil is not dependent upon the magnitude of the generated pulse but instead is provided by the battery, the voltage across the secondary of the ignition coil is approximately the same regardless of the speed of the engine. Furthermore, the elimination of the make and break contacts eliminates a critical part of the ignition system and one which must be constantly maintained since the distributor breaker points contaminate and wear out rapidly.

DESCRIPTION OF THE DRAWINGS The invention together with these and other objectives and attendant advantages will be better under stood from the detailed description below taken together with the accompanying drawings in which:

FIG. 1 is a schematic sectional view of a pulse generating wire andsensor used in the ignition system of this invention.

FIG. 2 is a plan view of the triggering means of the ignition system of this invention.

FIG. 3 is a sectional view taken along lines 33 of FIG. 2.

FIG. 4 is an end view of the sensor of FIG. 2.

FIG. 5 is a schematic circuit diagram of the ignition system of this invention.

FIG. 6 is a perspective view, partially schematic, of a preferred form of ignition distributor of this invention.

DETAILED DESCRIPTION Before discussing the details of the present invention, it is important that one understands the structure and operation of the primary element of the ignition distributor of this invention. To this end reference is made to U.S. Pat. application, Ser. No. 173,070 filed Aug. 19, 1971 entitled Self-Nucleating Magnetic Wire and filed by the inventor of the present invention. The subject matter of that co-pending application is incorporated herein. For facilitating understanding of this invention a brief description, with reference to FIG. 1, of the selfnucleating magnetic wire follows. A magnetizable wire 10 is treated to form a shell 12 and central core 14, the shell having the capacity to be permanently magnetized in an axial direction and having high coercivity. The core 14 has a relatively low coercivity. Such a wire can be formed by drawing a wire of ferro-magnetic material and work-hardening the wire such as by circumferentially straining it to form a relatively hard" magnetic wire shell 12 having relatively high magnetic retentivity and coercivity. The wire has a relatively soft" magnetic core 14 having relatively low coercivity. Both the shell and the core are magnetically anisotropic with an easy axis of magnetization parallel to the axis of the wire 10. The wire is then magnetized by subjecting it to an external magnetic field. The relatively hard shell 12 has a retentivity and coercivity sufficiently greater than that of the relatively soft" core 14 so that when the external magnetic field is removed the shell retains its charge and couples or captures" the core by magnetizing the core in an axial direction opposite to the direction of magnetization of the shell. In this fashion the core 14 forms a magnetic return path or shunt for the shell 12 as shown by flux lines illustrated in FIG. I and a domain wall interface is formed between the core and shell.

When the wire 10 is subjected to an external magnetic field of greater magnitude than the field of the shell and having a polarity opposite to that of the shell, such as by bringing a permanent magnet 16 into close proximity to the wire 10, the external field to which the wire is subjected increases until a point is reached at which time the external magnet 16 captures the core 14 from the shell 12 by reversing the flux direction of the core through the process of nucleation of a magnetic domain. Reversal of the field direction of the core results in an abrupt change in the magnetic flux surrounding the wire 10. When the permanent magnet 16 is removed from the wire 10 the shell recaptures the core providing an additional abrupt and more pronounced change in the magnetic flux surrounding the wire. In general, the rate of propagation of the domain wall along the wire is a function of the wire composition, metallurgical structure, diameter and length and of the strength of the external magnetic field. A coil 18 placed adjacent to the wire 10 will have a current pulse induced therein by this abruptly changing magnetic field and that current pulse may then be utilized as described below.

A plurality of such wires 10 is used to form the triggering means of the ignition distributor of this invention. With reference now to FIGS. 2 and 3 there is illustrated a rotor 20 having an annular rim or flange 22, a hub 24 having a central opening 26 for receiving a distributor drive shaft 28 and an intermediate web 30 connecting the flange 22 and hub 24. A plurality of equiangularly spaced straight wires 10 are mounted in axially extending partially circular recesses 32 formed on the outer surface of the flange 22. It has been found that for an ignition distributor the wire preferably is made from an alloy of 48 percent iron and 52 percent nickel, with each wire having a diameter of approximately 0.0159 inch and a length of approximately 0.625 inch. The number of wires is an integral function of the number of spark plugs intended to be fired. For example, in a 6 cylinder engine having 6 spark plugs, 6 wires are equiangularly spaced about the periphery of the rotor 20 or, in other words, the wires are spaced apart 60. For certain applications it may be desired to utilize fewer wires, such as 3, and to rotate the rotor 20 sufficiently fast so as to allow each wire to service 2 spark plugs, or to utilize more wires, such as 12, and reduce the speed of rotor rotation. It also is possible to utilize a single wire 10 to tire a plurality of spark plugs with a different spark plug being fired with each revolution of the rotor 20. This will be better understood from the detailed description below of the entire ignition distributor system and the relevance of the wire in the timing of the spark plug firing.

A sensor or readout head 40 is mounted in close proximity to the outer surface of the flange 22 at a position which shall be referred'to throughout as the sensing station 42. The function of the readout head 40 is to acknowledge, through generation of a signal, the presence of a wire 10 at the sensing station 42. The readout head 40 comprises an inductive sensor 44 having a pickup coil 46 encircling the center bridge 48 of a generally square-A shaped soft iron laminated pickup core 50. The core 50, in addition to the center bridge 48, further includes a pair of parallel legs 52, 54 and a rear bridge 56 with the free ends of the legs 52, 54 serving as pickup poles and being located in close proximity to the outer surface of the distributor rotor flange 22.

The readout head 40 also includes a pair of opposed U-shaped permanent magnets 60, 62 which preferably are substantially identical and have substantially equal magnetic characteristics. The permanent magnets 60, 62 are mounted on opposite sides of the inductive sensor 44 and in engagement with the pickup core 50. The two permanent magnets 60, 62 are mounted in opposed magnetic relationship such that each pole of each magnet faces an opposite pole of the other magnet (see FIG. 4). The opposed permanent magnets 60, 62 are laterally offset in opposite lateral directions relative to a plane 64 extending through the pickup core 50. This is accomplished by having the like inner poles (for example-north) of the permanent magnets 60, 62 engaging the sides of the legs 52, 54 of the pickup core 50. The readout head 40 is mounted so that the plane 64 extending through the pickup core center line is inclined (approximate 12 as shown in FIG. 4) to the axis of the rotor 20. However, because the permanent magnets are laterally offset with respect to the pickup core 50, the permanent magnetic field between the opposed permanent magnets 60, 62 is substantially parallel to the axis of the rotor 20 and magnetic wires at the sensing station 42. Furthermore, since the polarity of the fields on opposite sides of the pickup core 50 are equal in magnitude and opposite in polarity a zero or null magnetic field position is established midway between the permanent magnets. For controlling the magnetic fields surrounding the readout head 40, it has been found helpful to employ a thin U-shaped soft iron magnetic shield 66 around the back and partially around the sides of the inductive sensor with the sides of the shield 66 extending generally parallel to the axis of the magnetic wires 10.

Assuming that the rotor rotates in a clockwise direction as viewed in FIG. 2, the magnetic wires tend to pass from left to right across the readout head 40 as viewed in FIG. 4. As each wire approaches the sensing station 42 its shell 12 is subjected to the leading" permanent magnetic field 67 of the readout head 40 which has been set to have the opposite magnetic orientation as the wire shell 12. In the example illustrated in FIG. 4 the wire shell 12 has its south pole at its upper end and north pole at its lower end which is opposite to the orientation of the left side of the permanent magnets 60, 62. Before the wire 10 reaches the influence of the leading permanent magnetic field 67 the wire core 14 has its north pole at itsupper end and south pole at its lower end due to the induction of suchan orientation by the dominant shell 12. When the wire l0is in the leading permanent magnetic field 6,7 th'erleft side'of the permanent magnets 60,62 captures the core 14 from the'shell l2 andreverses its magnetic orientation so that the upper end of the wirecore becomes south and the lower end north. However, as the wire passes the leading magnetic field 67 it approaches the null position where the magnetic fielddue tothe permanent magnetic field is zero. When the magnetic field of the permanent magnets 60, 62 drops below a certain level depending upon the strength of the shell12, the shell recaptures the core 14 and reverses the cores magnetic t field. The resultant nucleation causing the core reversal produces an abrupt change in the magnetic field to which the inductive sensor coil 46 is exposed inducing a strong electrical pulse in the inductive sensor 44. Because of the inclination of the readouthead 40 one end of the wire 10 (in this present case upper end) sees the reduced magnetic field of the permanent magnets or the null position before the other end thereby ensuring that the direction of propagation of the domain wall always is the same and the induced pulse polarity always is the same.

When the wire passes the null position 42 it enters the trailing field 68 of the permanent magnets 60, 62 which has an orientation coinciding with that of the wire shell 12 and, therefore, has no effecton the core 14.

IGNITION SYSTEM (FIGS. 5 AND 6) Turning now to FIG. 5 there is illustrated a schematic diagram showing the ignition distribution system and associated circuitry. The system 100 can be divided into three basic segments, the primary circuit 101, the triggering means 102 and the secondary circuit 103. The primary circuit 101 includes a low voltage battery 104, in the order of6 or l2 volts, connected.

in series with an ignition switch 105 and a primary winding 106 of an ignition coil 108, all of which are included in conventional ignition systems. The primary circuit 101 also includes a normally open electronic valve 110 such as a semiconductor controlled rectifier (SCR) connected in series with the battery 104 and primary winding 106.

The triggering means comprises the rotor 20 and readout head 40 discussed above operatively connected to the control element or base 112 of the electronic valve 110 preferably throughan amplifier 114. The normally open electronic valve 110 prevents current from passing through the primary winding 106 until there is an occurrence of a predetermined event.

Such an event occurs when a wire 10 mounted on the rotor 20, after reaching the sensing station 42 and having thedirection of magnetization of the core 14 captured and reversed by the leading permanent magnetic field67 of the readout head 40, approaches the null position where the shell 12 recaptures core and abruptly reverses its direction of magnetization. The reversal caused by the shell 12 abruptly changes the magnetic field to which the inductive sensor 44 of the readout head 40 is subjected inducing a strong electric. current pulse in the inductive sensor 46. That pulse is amplified by the amplifier 114 to a levelat least high enough to trigger the electronic valve 110 closing the valve and permitting the current to flow through the primary winding 106 of the ignition coil 108. In some instances the induced pulse can be strong enough to trigger the electronic valve directly eliminating the need for an amplifier 114.

The increase of current through the primary winding cent to a distributor disk 124. A plurality of contacts 126, such as a tungsten electrode for each spark plug 116 or cylinder of the engine, are mounted about the periphery of the disk 124 so that as the distributor rotor 126 rotates it sequentially touches the contacts 126 providing a path for the current from the secondary winding 118 to the spark plugs 116 through conductors 128.

It is mentioned above that the triggering pulse is produced by the abrupt change in magnetic flux at the sensing station caused by the wire shell 12 reversing the wire cores polarity. It is also clear that the magnetic flux will be abruptly changed when the cores polarity is reversed by the leading permanent magnetic field 67. The flux change caused by the leading magnetic field 67 is of a significantly smaller magnitude than that of the change caused by the shell. The location of the peak of the leading field 67 is established at a distance from the pickup coil 46 such that the flux change resulting from the reversal of the wire cores polarity when captured by the magnets 60, 62 produces a pulse in the pickup coil 46 of less than a predetermined magnitude so that the electronic valve 110 is not closed. However, the peak of the leading field 67 must be close enough to the coil so that the shells recapturing of the wire core 14 as the wire passes the leading field peak takes place close enough to the pickup coil to produce the electronic valve triggering signal. Since it is essential that the spark plugs or other combustion ignition devices fire at precisely the right moment, it is important that alarge current surge take place through the primary winding 106 upon the triggering of the electronic valve 110. In order to improve the response time of the primary winding 106, a capacitor 130 is placed across the primary winding 106. The capacitor is charged by the battery 104 and when the electronic valve 110 is fired the capacitor 130 discharges through the primary winding 106 making additional current available to more rapidly increase the magnetic field of the primary winding 106. The distributor rotor 122 directs the high voltage to each spark plug in the proper firing order and each contact 126 corresponds with a particular spark plug 116 and a particular wire on the primary rotor 20.

If desired, and in order to further insure that combustion takes place within each cylinder at the desired time, one or more backup wires can be added behind each primary wire 10 so that if the spark generated by the first wire did not sufficiently ignite the gas in the cylinder, the subsequent sparks generated by the adjacent backup wires would insure total ignition.

FIG. 6 illustrates the mounting of the ignition distribution system 100 in a manner which facilitates substitution of this system for conventional ignition systems. The rotor is mounted on a distributor shaft 28 which, through a conventional pinion 1 and worm gear arrangement 138, is driven by an engine cam shaft 140. The distributor rotor 122 also is mounted on the distributor shaft 28 so that it rotates in conjunction with the rotor 20. The distributor disk 124 is fixedly mounted to the distributor casing 142 and may form the cover of the casing. The contacts 126 are equiangularly spaced about the periphery of the disk 124. With this particular arrangement the ignition timing is a function of the cam shaft speed or, in other words, engine speed.

Such a system also lends itself to control of the timing of pulse generation and spark plug firing depending upon the occurrence of one or more predetermined conditions. For example, instead of directly connecting the distributor shaft 28 to the cam shaft 140, an electromagnetic clutch (not shown) can be used which is controlled by one or more signals representative of conditions such as temperature, manifold pressure, engine speed, etc. The speed and phase of rotor rotation can be varied by the clutch as a function of these conditions.

While the above described triggering means has the wires 10 mounted on a rotor, the pulses induced in the induction sensor 44 also could be obtained by providing relative reciprocating motion between the wires 10 and the inductive sensor 46 such as by mounting the wires on an oscillating member (not shown).

It will be appreciated that in place of the constantly impacting, sparking distributor points of a conventional ignition distributor, this invention provides a special non-contact system including merely a rotating member 20 with a plurality of specially fabricated wires 10 and a solid state readout head including basically a coil 46 and a pair of permanent magnets 60, 62. A sharply defined pulse of substantially constant magnitude is generated each time a wire 10 passes the sensing station 42 thereby accurately timing the firing of the spark plugs regardless of engine speed.

In addition to being low in cost, simple to manufacture, and essentially maintenance free, the ignition system of this invention improves the accuracy of timing since it does not depend upon spring constants nor is it subjected to contact arcing or pitting. The ignition system is not sensitive to the engine speed and provides exact timing regardless of engine speed.

What is claimed as new and desired to be secured by Letter Patent of the United States is:

1. An ignition system comprising a primary circuit, a secondary circuit and triggering means,

a. the secondary circuit including a secondary winding, a distributor electrically responsive to the secondary winding, a plurality of contacts each of which is adapted to be electrically connected to a combustion ignition device, the distributor being mounted to permit relative motion between it and the contacts to effect sequential electrical connection between the secondary winding and the contacts,

b. the primary circuit including in series arrangement an electrical energy source, a primary winding and an electronic valve, the primary winding being in inductive relationship with the secondary winding,

and

c. the triggering means including i. a magnetic device having:

a first magnetic domain, and

a second magnetic domain,

at least said first domain being capable of retaining net magnetization after being subjected to a magnetic field,

the magnitude of at least one of the magnetic properties of said first domain being substantially different than the magnitude of the corresponding magnetic property of said second domain,

said domains being separated by a domain wall when said first domain has a net magnetization in a first direction and said second domain has a net magnetization in a second direction substantially opposite from said first direction,

ii. magnetic means for producing a magnetic field sufficient to reverse the net magnetization of said second domain from said second direction to said first direction,

iii. control means for subjecting said magnetic device to said magnetic means in response to predetermined criteria, and

iv. means for sensing a change in the magnetic flux adjacent to said magnetic device,

d. the electronic valve being responsive to the sensing means to permit electric current from the electrical energy source to fiow through the primary winding upon occurrence of the flux change to induce a current in the secondary winding for supplying electrical energy to the contacts.

2. An ignition system as defined in claim 1 wherein the sensing means includes a coil of conductive wire mounted immediately adjacent said magnetic means.

3. An ignition system as defined in claim 1 wherein the magnetic means for producing the magnetic field is a permanent magnet.

4. An ignition system as defined in claim 3 wherein the permanent magnet and the magnetic device are mounted for movement relative to one another.

5. An ignition system as defined in claim 4 wherein the movement is controlled by the control means.

6. An ignition system as defined in claim 4 wherein said magnetic device is mounted on a rotor mounted for rotary movement adjacent to the sensing means and permanent magnet.

7. An ignition system as defined in claim 6 including a distributor shaft drivingly connected to an engine cam shaft and wherein the rotor is drivingly connected to said shaft. t

8. An ignition system as defined in claim 7 wherein the distributor is mounted for rotary motion relative to the contacts and wherein rotation of the distributor rotates is in direct relation to rotation of the rotor.

9. An ignitibn system as defined in claim 8 wherein the number of contacts and magnetic devices equal the number of combustion ignition devices to be fired and each magnetic devices corresponds to a particular contact.

10. An ignition system as defined in claim 8 wherein the number of contacts and said magnetic devices equal the number of combustion ignition devices to be fired and the distributor is drivingly connected to the distributor shaft.

11. An ignition system as defined in claim 4 including a capacitor mounted across the primary winding.

12. An ignition system as defined in claim 4 wherein the sensing means provides a signal indicating the occurrence of the fiux change, the electronic valve being responsive to the sensing means signal.

13. An ignition system as defined in claim 12 including an amplifier for amplifying the signal and wherein the electronic valve has a control element, the amplified signal being directed to the control element such that upon the receipt of the amplified signal the electronic valve is closed.

14. An ignition system as defined in claim 13 wherein the electronic valve is a semiconductor controlled rectifier.

15. An ignition system as defined in claim 12 including a set of magnetic devices for each combustion ignition device to be fired, each set of magnetic devices providing a plurality of signals equal in number to the number of magnetic devices in the set and wherein the plurality of signals is provided while the distributor is in electrical contact with the contact corresponding to the magnetic device set providing the signals.

16. An ignition system as defined in claim 12 wherein the number of magnetic devices is an integral multiple of the number of combustion ignition devices intended to be fired and wherein each magnetic device is a wire of an alloy of 48 percent iron and 52 percent nickel.

17. An ignition system as defined in claim 16 wherein each wire has a diameter approximately 0.0159 inch and a length approximately 0.625 inch.

18. An ignition system as defined in claim 4 wherein the criteria is the speed of an engine in which the combustion ignition devices are mounted.

19. An ignition system for an internal combustion engine comprising:

a. a secondary circuit including a secondary winding in series with an electrically conductive distributor rotor, a plurality of fixed contacts spaced equiangularly about a disc, each contact corresponding to and adapted to be electrically connected to a spark plug, the distributor rotor being mounted for rotary movement relative to the contacts and to effect sequential electrical connection between the secondary winding and the contacts,

b. a primary circuit including in series arrangement a battery, a primary winding and an electronic valve having a control element, the primary winding being in inductive relationship with the secondary winding,

c. triggering means including i. a primary rotor having a plurality of wires mounted thereon, the primary rotor and distributor rotor being driven by the engine, the number of wires being an integral multiple of the number of fixed contacts, each wire having a first magnetic domain, and a second magnetic domain, at least said first domain being capable of retaining net magnetizationafter being subjected to a magnetic field, the magnitude of at least one of the magnetic properties of said first domain being substantially different than the magnitude of the corresponding magnetic property of said second domain, said domains being separated by a domain wall whensaid first domain has a net magnetization in a first direction and'said second domain has a net magnetization in a second direction substantially opposite from said first direction.

ii. a permanent magnet mounted adjacent to the primary rotor for producing a magnetic field to effect reversal of the direction of magnetization of the second domain tosaid first direction when the wireis juxtaposed to thepermanent magnet, the direction of magnetization of the second domain being reversed as the wire leaves the said magnetic field.

iii. sensing means including a coil conductive wire immediately adjacent to the permanent magnet for sensing a change in magnetic flux, the sensing means providing a signal indicating the occurrence of the flux change, the signal being diwhich effected the signal.

20. An ignition system as defined in claim 19 wherein the sensing means provides a signal to which the electronic valve is responsive only upon occurrence of the flux change caused by the wire leaving the said magnetic field. 

1. An ignition system comprising a primary circuit, a secondary circuit and triggering means, a. the secondary circuit including a secondary winding, a distRibutor electrically responsive to the secondary winding, a plurality of contacts each of which is adapted to be electrically connected to a combustion ignition device, the distributor being mounted to permit relative motion between it and the contacts to effect sequential electrical connection between the secondary winding and the contacts, b. the primary circuit including in series arrangement an electrical energy source, a primary winding and an electronic valve, the primary winding being in inductive relationship with the secondary winding, and c. the triggering means including i. a magnetic device having: a first magnetic domain, and a second magnetic domain, at least said first domain being capable of retaining net magnetization after being subjected to a magnetic field, the magnitude of at least one of the magnetic properties of said first domain being substantially different than the magnitude of the corresponding magnetic property of said second domain, said domains being separated by a domain wall when said first domain has a net magnetization in a first direction and said second domain has a net magnetization in a second direction substantially opposite from said first direction, ii. magnetic means for producing a magnetic field sufficient to reverse the net magnetization of said second domain from said second direction to said first direction, iii. control means for subjecting said magnetic device to said magnetic means in response to predetermined criteria, and iv. means for sensing a change in the magnetic flux adjacent to said magnetic device, d. the electronic valve being responsive to the sensing means to permit electric current from the electrical energy source to flow through the primary winding upon occurrence of the flux change to induce a current in the secondary winding for supplying electrical energy to the contacts.
 2. An ignition system as defined in claim 1 wherein the sensing means includes a coil of conductive wire mounted immediately adjacent said magnetic means.
 3. An ignition system as defined in claim 1 wherein the magnetic means for producing the magnetic field is a permanent magnet.
 4. An ignition system as defined in claim 3 wherein the permanent magnet and the magnetic device are mounted for movement relative to one another.
 5. An ignition system as defined in claim 4 wherein the movement is controlled by the control means.
 6. An ignition system as defined in claim 4 wherein said magnetic device is mounted on a rotor mounted for rotary movement adjacent to the sensing means and permanent magnet.
 7. An ignition system as defined in claim 6 including a distributor shaft drivingly connected to an engine cam shaft and wherein the rotor is drivingly connected to said shaft.
 8. An ignition system as defined in claim 7 wherein the distributor is mounted for rotary motion relative to the contacts and wherein rotation of the distributor rotates is in direct relation to rotation of the rotor.
 9. An ignition system as defined in claim 8 wherein the number of contacts and magnetic devices equal the number of combustion ignition devices to be fired and each magnetic devices corresponds to a particular contact.
 10. An ignition system as defined in claim 8 wherein the number of contacts and said magnetic devices equal the number of combustion ignition devices to be fired and the distributor is drivingly connected to the distributor shaft.
 11. An ignition system as defined in claim 4 including a capacitor mounted across the primary winding.
 12. An ignition system as defined in claim 4 wherein the sensing means provides a signal indicating the occurrence of the flux change, the electronic valve being responsive to the sensing means signal.
 13. An ignition system as defined in claim 12 including an amplifier for amplifying the signal and wherein the electronic valve has a control element, the amplified signal being directed to the control element such that upon The receipt of the amplified signal the electronic valve is closed.
 14. An ignition system as defined in claim 13 wherein the electronic valve is a semiconductor controlled rectifier.
 15. An ignition system as defined in claim 12 including a set of magnetic devices for each combustion ignition device to be fired, each set of magnetic devices providing a plurality of signals equal in number to the number of magnetic devices in the set and wherein the plurality of signals is provided while the distributor is in electrical contact with the contact corresponding to the magnetic device set providing the signals.
 16. An ignition system as defined in claim 12 wherein the number of magnetic devices is an integral multiple of the number of combustion ignition devices intended to be fired and wherein each magnetic device is a wire of an alloy of 48 percent iron and 52 percent nickel.
 17. An ignition system as defined in claim 16 wherein each wire has a diameter approximately 0.0159 inch and a length approximately 0.625 inch.
 18. An ignition system as defined in claim 4 wherein the criteria is the speed of an engine in which the combustion ignition devices are mounted.
 19. An ignition system for an internal combustion engine comprising: a. a secondary circuit including a secondary winding in series with an electrically conductive distributor rotor, a plurality of fixed contacts spaced equiangularly about a disc, each contact corresponding to and adapted to be electrically connected to a spark plug, the distributor rotor being mounted for rotary movement relative to the contacts and to effect sequential electrical connection between the secondary winding and the contacts, b. a primary circuit including in series arrangement a battery, a primary winding and an electronic valve having a control element, the primary winding being in inductive relationship with the secondary winding, c. triggering means including i. a primary rotor having a plurality of wires mounted thereon, the primary rotor and distributor rotor being driven by the engine, the number of wires being an integral multiple of the number of fixed contacts, each wire having a first magnetic domain, and a second magnetic domain, at least said first domain being capable of retaining net magnetization after being subjected to a magnetic field, the magnitude of at least one of the magnetic properties of said first domain being substantially different than the magnitude of the corresponding magnetic property of said second domain, said domains being separated by a domain wall when said first domain has a net magnetization in a first direction and said second domain has a net magnetization in a second direction substantially opposite from said first direction. ii. a permanent magnet mounted adjacent to the primary rotor for producing a magnetic field to effect reversal of the direction of magnetization of the second domain to said first direction when the wire is juxtaposed to the permanent magnet, the direction of magnetization of the second domain being reversed as the wire leaves the said magnetic field. iii. sensing means including a coil conductive wire immediately adjacent to the permanent magnet for sensing a change in magnetic flux, the sensing means providing a signal indicating the occurrence of the flux change, the signal being directed to the control element of the electronic valve, d. the electronic valve being responsive to the signal such that it closes upon receipt of the signal permitting the battery to energize the primary winding inducing a current in the secondary winding and supplying electrical energy through the distributor rotor to the contact corresponding to the wire which effected the signal.
 20. An ignition system as defined in claim 19 wherein the sensing means provides a signal to which the electronic valve is responsive only upon occurrence of the flux change caused by the wire leaving the said magnetic field. 